It is known that some lytic peptides are active against a broad range of organisms while others produce little or no effect. It is also known that one target of the lytic peptides is the membrane. The amino acid sequence of several lytic peptides with antimicrobial activity are disclosed in Jaynes et al., PCT patent application Ser. No. US88/03908.
Hydrolytic enzymes, such as chitinase and beta-1,3-glucanase, are known to inhibit fungal growth. Schlumbaum et al., Nature, 324:365-367 (1986); Mauch et al., Plant Phys., 88:936-942 (1988); and Burri, Diplomarbeit (1989). It is also well known that chitinase and beta-1,3-glucanase are strongly induced in beans by ethylene treatment. Furthermore, those enzymes can be purified quite easily. Boller et al., Planta, 157:22-31 (1983).
Lehrer et al., Infection and Immunity, 52:902-904 (1986) disclose six antimicrobial peptides (AMPs) from rabbit granulocytes that are structurally homologous to human neutrophil defensins. Three of the rabbit AMPs (NP-1, NP-2 and NP-3a) are disclosed to be effective against Candida albicans. Lehrer et al. further disclose that NP-5, although not directly fungicidal against C. albicans, demonstrated what is termed a synergistic effect, an increase in the fungicidal activity of NP-1, when the fungus was exposed to both NP-5 and NP-1.
Ogasawara et al., Chem. Abstracts, 79: 13362v (1973) disclose that the combination of beta-1,3-glucanase and chitinase is an effective fungicide and bactericide useful in the treatment of rice.
Jaynes et al., PCT International Application No. PCT/US87/01710 discloses the inhibition of crop damage from lepidoptera larvae by expressing genes which code for chitinase enzyme in the target crop.